1. (noun) A tool that is run across surfaces to clean or style it in some manner. See hair brush, tooth brush, etc. Made of tiny bristles or teeth that scrape dirt out, scratch the surface, and remove loose things.

2. (verb) To run an appropriate brush across the surface it was designed for, the process of cleaning.

3. (noun) Loose vegetation (often dead) found low to the ground.

4. (verb) To loosely touch without purpose.

I bought a brush today.
I brushed my teeth with my tooth brush.
I brushed my hair with my hair brush.
When the bear ran at me, I hid in the brush.
I brushed her arm as I passed by.
I apologized, and then brushed past her as I took the only means out of the room.